Subway says it’s in the process of removing a chemical from its bread as part of an ongoing effort to improve its recipes.

The announcement comes after a popular food blogger launched a petition this week asking the sandwich chain to stop using the ingredient, called azodicarbonamide. A representative for Subway says the change was underway before the petition was launched, but did not immediately provide details on when it started or when it would be complete.

“The complete conversion to have this product out of the bread will be done soon,” Subway said in a statement, without providing further details.